The relationship of bird diversity to crop and non-crop heterogeneity in agricultural landscapes

• DOI: 10.1007/s10980-015-0226-0
• Publication Date: 2015-06-11T06:01:48Z
• Authors: Matthew Hiron; Åke Berg; Sönke Eggers; Åsa Berggren; Jonas Josefsson; Tomas Pärt
• Keywords: 2. Zero hunger; 0106 biological sciences; 14. Life underwater; 15. Life on land; 01 natural sciences

Context Habitat heterogeneity is often assumed to benefit farmland biodiversity. Increasing heterogeneity of non-crop habitats is often too costly in terms of agricultural production. It has been suggested that increased crop heterogeneity could mitigate the negative effects of intensification on biodiversity while still maintaining high production levels. Objectives We investigated if habitat-specific species pools of two groups of farmland birds, fieldnesting and non-crop-nesting species, were related to landscape-level heterogeneity of crop and non-crop cover. We analysed total number of species (gamma diversity) and average local species richness (alpha diversity) in landscapes and related these two biodiversity measures to four components of landscape heterogeneity (compositional and configurational heterogeneity of crop and non-crop cover). Methods We selected 30 farmland landscapes (each 25 km 2 ) in Sweden that largely broke up correlated relationships between crop and non-crop heterogeneity and between compositional and configurational heterogeneity. Estimates of species richness (alpha and gamma diversity) were calculated with bird survey data from specific habitats within landscapes (farmsteads and arable fields) and then related to measures of landscape heterogeneity. Results No measure of landscape species richness was associated with landscape-scale crop cover heterogeneities. However, gamma diversity of both bird groups was negatively related to the compositional and configurational heterogeneity of non-crop land-use in the landscapes, respectively. Conclusions Our results suggest that: (i) crop heterogeneities are not related to habitat-specific richness of farmland birds, (ii) heterogeneity effects of habitat complementarity in general are weak and (iii) relationships between diversity and heterogeneity in landscapes are dependent on the biodiversity measure used.